Tooth root canal anchorage assembly

Abstract

The tooth root channel anchorage assembly comprises a core member to be fixed within the tooth root channel and a post to be inserted into the core member having a thoroughgoing bore. The core member comprises a crown part and an anchorage part to be fixed within the root canal, the surface of the anchorage part having a substantially hyperbolic form. Preferably the crown part of the core member as well as a part of the surface of the post have also a substantially hyperbolic form. The hyperbolic form allows a better anchoring and distributing of the load, thus reducing the danger of breaking of the post and root canal, still allowing the access to the root canal before the post is inserted.

1. A tooth root channel anchorage assembly, comprising:
 a core member configured to be fixed within the tooth root channel; and 
 a post configured to be inserted into the core member,
 the core member further comprising a thoroughgoing bore, wherein 
 
 said core member further comprises a crown part and an anchorage part configured to be fixed within the root canal, and wherein 
 a surface of the anchorage part has a substantially hyperbolic form, and 
 the post further comprises:
 a cylindrical part configured to slidably fit into the bore of the core member, and 
 a post anchorage part following the cylindrical part and including a surface with a hyperbolic form. 
 
 
     
     
       2. An assembly according to  claim 1 , wherein the crown part of the core member comprises a surface which has a substantially hyperbolic form. 
     
     
       3. An assembly according to  claim 1 , wherein the core member and the post are made of fibre glass reinforced composite material. 
     
     
       4. An assembly according to  claim 1 , wherein said hyperbolic form is a hyperboloid of revolution of one sheet, according to the formula: 
       
         
           
             
               
                 
                   
                     
                       
                         
                           x 
                           2 
                         
                         
                           a 
                           2 
                         
                       
                       + 
                       
                         
                           y 
                           2 
                         
                         
                           b 
                           2 
                         
                       
                       - 
                       
                         
                           z 
                           2 
                         
                         
                           c 
                           2 
                         
                       
                     
                     = 
                     1 
                   
                 
                 
                   
                     ( 
                     1 
                     ) 
                   
                 
               
             
           
         
         whereby a=b, and the asymptote is defined as having an angle 
       
       
         
           
             
               α 
               = 
               
                 
                   c 
                   b 
                 
                 . 
               
             
           
         
       
     
     
       5. An assembly according to  claim 4 , wherein the core member has the following values:
 a=b, a greatest diameter (R 5 ) of the core member=3-5 mm, a smallest diameter (R 1 ) of the crown surface=2-4 mm, a smallest diameter (R 2 ) of the anchorage surface=1.5-3 mm, a distance (D 1 ) between the beginning of the hyperbolic surface and the greatest diameter (R 5 )=1.5-3 mm, and a distance (D 2 ) between the greatest diameter (R 5 ) and the end of the anchorage part (R 2 )=1.5-3 mm. 
 
     
     
       6. An assembly according to  claim 4 , wherein the post has the following values:
 a=b, a diameter (R 3 ) of the cylindrical part=1.3-1.7 mm, a diameter (R 4 ) of the end of the post=0.3-0.7 mm, a distance (D 3 ) between (R 3 ) and (R 4 )=8-12 mm. 
 
     
     
       7. An assembly according to  claim 1 , further comprising a first drill having a first drilling surface with the same shape as the anchorage part of said core member and a second drill having a second drilling surface with the same shape as the post part which is configured to be inserted into the root channel. 
     
     
       8. An assembly according to  claim 1 , further comprising a first reamer having a first reaming surface with the same shape as the anchorage part of said core member and a second reamer having a second reaming surface with the same shape as the post part which is configured to be inserted into the root channel.